As a heads-up display for vehicles which is a type of display device, for example, a liquid crystal panel having display information is disposed inside the instrument panel in the vehicle interior and light from a backlight transmitted through the liquid crystal panel is emitted toward the front windshield by a reflecting mirror. This emitted light is incident on the eyes of the driver after being reflected by the front windshield, and the driver can see the display information from the liquid crystal panel as a virtual image. In a vehicle, it is important to reduce the effect of thermal energy on the liquid crystal panel due to infrared rays (infrared light) in external light (sunlight).
Japanese Unexamined Patent Application Publication No. H11-23997A discloses a heads-up display for vehicles in which a filter is provided in front of the liquid crystal panel to block infrared light incident on the liquid crystal panel.